Glitter bombs have officially gone from annoying viral prank to national security issue after a Nebraska congressman received one in the mail earlier this week.

A hot pink letter arrived at Rep. Jeff Fortenberry's Lincoln, Nebraska office on Wednesday, with a bag of glitter inside, reported WOWT. The stunt seems to be the work of an activist: The letterhead was titled "Glitter Bombs For Choice" and the note said, "Congrats! You've earned this for trying to deny women their right to choice. Mind your own uterus." (According to On The Issues, Rep. Fortenberry voted to ban federal health coverage for abortion in 2011.)

This has sparked an investigation from the FBI, the U.S. Postal Service and local police.

WOWT

The congressman responded to the prank with a stern statement: "Anyone is free to disagree with me, but to resort to these tactics in a heightened threat environment is reckless and a waste of precious law enforcement resources."